The application of powdered porcelain enamel to sanitary ware appliances, such as for instance metal bathtubs, sinks and the like, has traditionally been carried out by heating the article or casting to be coated to a predetermined temperature, withdrawing the casting from the heating furnace and placing it in a cradle adapted to be tilted through a 90.degree. arc and rotatable approximately 360.degree., with an operator standing over the hot casting and manually sifting powdered porcelain enamel onto the heated article and while it is manipulated in the cradle to present various surfaces to the cascading powder coating material.
The heat of the base metal of the article causes the powdered porcelain enamel coming in contact therewith to fuse and adhere thereto, and the process is usually repeated with reheating of the casting two or three times until a sufficiently thick coating of vitreous enamel has been built up on the surface of the article, to thereby provide a protective coating thereto. Following the enameling procedure, the casting is allowed to cool, whereupon the vitreous coating becomes hard and glossy, and the article is ready for distribution and installation. The manual application of the particulate material to the article is an expensive and time consuming procedure, and has presented many problems.